Work in progress involves: 1) The isolation and purification of several lung proteases which appear to be involved in specific immunologic injury to rabbit lung. 2) The characterization of each of these enzymes, with regard to chemical, physical and biological properties. 3) The production of antibodies to each of these enzymes. 4) The utilization of these antibodies for determining the cellular and subcellular localization of each of these enzymes in normal and impaired lung.